The objective of the research is to develop methods of data analysis and an accompanying computer methodology designed to aid in the evaluation of family planning programs. The methods of data analysis under development are designed to utilize data collected in either large clinical trials, longitudinal surveys, or cross-sectional surveys. Particular attention will be given to the problem of estimating the number of accepters of IUD's, pills, and other methods of contraception, abortion and sterilization, by various demographic characteristics, required to attain given reductions in fertility as prescribed by population policies. A central part of the research will consist of constructing statistical models of human reproduction describing patterns actually followed by couples in utilizing contraception, abortion, and sterilization to space and limit births. Data from Taiwan, the United States, and elsewhere will be used to construct these statistical models.